int S3fsMultiCurl::MultiPerform()

in src/curl_multi.cpp [107:179]
63 lines of code
16 McCabe index (conditional complexity)

int S3fsMultiCurl::MultiPerform()
{
    std::vector<pthread_t>   threads;
    bool                     success = true;
    bool                     isMultiHead = false;
    Semaphore                sem(GetMaxParallelism());
    int                      rc;

    for(s3fscurllist_t::iterator iter = clist_req.begin(); iter != clist_req.end(); ++iter) {
        pthread_t   thread;
        S3fsCurl*   s3fscurl = *iter;
        if(!s3fscurl){
            continue;
        }

        sem.wait();

        {
            AutoLock lock(&completed_tids_lock);
            for(std::vector<pthread_t>::iterator it = completed_tids.begin(); it != completed_tids.end(); ++it){
                void*   retval;
    
                rc = pthread_join(*it, &retval);
                if (rc) {
                    success = false;
                    S3FS_PRN_ERR("failed pthread_join - rc(%d) %s", rc, strerror(rc));
                } else {
                    int int_retval = (int)(intptr_t)(retval);
                    if (int_retval && !(int_retval == -ENOENT && isMultiHead)) {
                        S3FS_PRN_WARN("thread terminated with non-zero return code: %d", int_retval);
                    }
                }
            }
            completed_tids.clear();
        }
        s3fscurl->sem = &sem;
        s3fscurl->completed_tids_lock = &completed_tids_lock;
        s3fscurl->completed_tids = &completed_tids;

        isMultiHead |= s3fscurl->GetOp() == "HEAD";

        rc = pthread_create(&thread, NULL, S3fsMultiCurl::RequestPerformWrapper, static_cast<void*>(s3fscurl));
        if (rc != 0) {
            success = false;
            S3FS_PRN_ERR("failed pthread_create - rc(%d)", rc);
            break;
        }
        threads.push_back(thread);
    }

    for(int i = 0; i < sem.get_value(); ++i){
        sem.wait();
    }

    AutoLock lock(&completed_tids_lock);
    for (std::vector<pthread_t>::iterator titer = completed_tids.begin(); titer != completed_tids.end(); ++titer) {
        void*   retval;

        rc = pthread_join(*titer, &retval);
        if (rc) {
            success = false;
            S3FS_PRN_ERR("failed pthread_join - rc(%d)", rc);
        } else {
            int int_retval = (int)(intptr_t)(retval);
            if (int_retval && !(int_retval == -ENOENT && isMultiHead)) {
                S3FS_PRN_WARN("thread terminated with non-zero return code: %d", int_retval);
            }
        }
    }
    completed_tids.clear();

    return success ? 0 : -EIO;
}